Protect against accidental table renames

lib/migration/safe_migrate.rb

@@ -84,26 +84,26 @@ class Migration::SafeMigrate
   end
 
   def self.protect!(sql)
-    if sql =~ /^\s*drop\s+table/i
+    if sql =~ /^\s*(?:drop\s+table|alter\s+table.*rename\s+to)\s+/i
       $stdout.puts("", <<~STR)
         WARNING
         -------------------------------------------------------------------------------------
-        An attempt was made to drop a table in a migration
+        An attempt was made to drop or rename a table in a migration
         SQL used was: '#{sql}'
-        Please use the deferred pattrn using Migration::TableDropper in db/seeds to drop
+        Please use the deferred pattern using Migration::TableDropper in db/seeds to drop
-        the table.
+        or rename the table.
 
         This protection is in place to protect us against dropping tables that are currently
         in use by live applications.
       STR
       raise Discourse::InvalidMigration, "Attempt was made to drop a table"
-    elsif sql =~ /^\s*alter\s+table.*(rename|drop)/i
+    elsif sql =~ /^\s*alter\s+table.*(?:rename|drop)\s+/i
       $stdout.puts("", <<~STR)
         WARNING
         -------------------------------------------------------------------------------------
         An attempt was made to drop or rename a column in a migration
         SQL used was: '#{sql}'
-        Please use the deferred pattrn using Migration::ColumnDropper in db/seeds to drop
+        Please use the deferred pattern using Migration::ColumnDropper in db/seeds to drop
         or rename columns.
 
         Note, to minimize disruption use self.ignored_columns = ["column name"] on your

spec/components/migration/safe_migrate_spec.rb

@@ -37,6 +37,22 @@ describe Migration::SafeMigrate do
     expect(User.first).not_to eq(nil)
   end
 
+  it "bans all table renames" do
+    Migration::SafeMigrate.enable!
+
+    path = File.expand_path "#{Rails.root}/spec/fixtures/migrate/rename_table"
+
+    output = capture_stdout do
+      expect(lambda do
+        ActiveRecord::Migrator.up([path])
+      end).to raise_error(StandardError)
+    end
+
+    expect(output).to include("TableDropper")
+
+    expect(User.first).not_to eq(nil)
+  end
+
   it "bans all column removal" do
     Migration::SafeMigrate.enable!
 

spec/fixtures/migrate/rename_table/20990309014014_rename_table.rb

@@ -0,0 +1,9 @@
+class RenameTable < ActiveRecord::Migration[5.1]
+  def up
+    rename_table :users, :persons
+  end
+
+  def down
+    raise "not tested"
+  end
+end